'At first we thought it was an equipment problem,' she said. It soon became clear that it was something else.

Indiana officials realized that the state's internal network had been hit by the SQL Slammer virus, which targeted a vulnerability in Microsoft 2000 SQL Server database software. Microsoft Corp. issued a patch last year.

Between 4 p.m. and 5 p.m., state officials took the network offline and blocked the port that uses SQL Server, Larimer said. By 7 p.m., all services were restored that did not run on SQL Server.

IT officials installed patches to the SQL Server software, and by 10 a.m. Monday, all Indiana's online services were back online, Larimer said.